1. Field of the Invention
The present invention relates to a cable penetration device.
2. Description of the Related Art
A cable penetration device, also called a cable transit device, that enables a plurality of cables to be fitted sealingly in an opening in the wall of a housing or some like structure is known, for instance, from U.S. Pat. Nos. 5,235,138, 4,267,401 or DE-U1-298 03 091, wherewith said device includes a rubber plug which has several through-penetrating channels that are plugged with removable stoppers and that are accessible from the circumferential edge of the plug via slits. A clamping plate is disposed on each side of the rubber plug and has openings corresponding to the channels. Tensioning bolts extend through the clamping plates and the rubber plug and function to cause the clamping plates to compress the rubber plug axially, therewith causing its channel walls to seal against cables that pass through the channels, and so that the plug circumference can be expanded into sealing contact with the wall opening of the cable transit device. The clamping plates must, of necessity, be rigid and takes-up a large part of the area of the wall opening. In addition, it is difficult to fit the cables correctly in practice, since the cables cannot be anchored sealingly in the device until the device is anchored sealingly in the transit opening.
A similar multi-cable transit device is known from SE-B-460 392.
A cable transit device that comprises a tubular sleeve at one end has an external thread for securing said device in a threaded opening through a wall or a housing, for instance a clutch housing, junction box or the like is known, for instance, from GB-A-22 80 317.
The tubular sleeve has at its other end a thread that co-acts with the thread of a nut. A rubber sleeve (gland) is disposed in the tubular sleeve between a circular shoulder on the nut and a circular shoulder in the tubular sleeve. The rubber sleeve is compressed axially by screwing in the nut thereby contracting the inner channel wall of the sleeve into sealing engagement around a cable that extends through the cable transit. The cable transit device is conventionally fitted to the housing and the cable is passed through said device and the ring-nut then tightened.
One problem with such cable transit devices is that they do not allow a pre-connected cable to be fitted easily, by pre-connected cable being meant a cable to which there has previously been connected to one end of a cable an electrical connector or contact that is larger than the bore of the rubber sleeve.
A further drawback is that the cable transit device only allows one single cable to be passed through.
An object of the present invention is to further develop a cable transit device of the aforesaid kind that will enable several cables, that may be pre-connected to an electrical device, to be passed through the device and secured sealingly at the same time on the one hand, and that can be pre-fitted in a wall opening and enable the cables to be sealingly fastened in a simple fashion on the other hand.
This object is achieved with a cable transit device including a tubular, elastic sleeve, and a plurality of elastic modules, each module containing at least one cable-accommodating, through-penetrating channel, with the modules together filling out an opening of the elastic sleeve, the opening having a shape that corresponds to the resultant outer contour of the mutually tightly combined modules. The device further includes a rigid sleeve having, at a first end portion, means for securing the rigid sleeve to a wall opening, the rigid sleeve having an inner circular shoulder against which the elastic sleeve is brought into abutment, and also having a thread at a second end portion. A nut that includes a support shoulder which co-acts with the elastic sleeve and that has a nut thread, interacts with the thread of the rigid sleeve, the nut having a cable-accommodating central opening. The rigid sleeve has an inner wall corresponding to an outer wall of the elastic sleeve, thereby enabling the cable transit device to be sealed by tightening the nut.
The sleeve is conveniently supported at each main surface by a support washer that includes an opening which is preferably slightly smaller than the sleeve orifice in the absence of load on said sleeve, so that the axial positional setting or retention of at least some of the modules between the support washers will be improved. Each module has a channel which is suitably filled initially, but which can be exposed. The modules are preferably divided, for instance in a plane axially to the channel, so as to enable the channel to be exposed by mutually separating the modules. The channel is normally plugged with a removable plug. The channel wall may be comprised of parallel layers of material that can be peeled away and therewith give the channel a selectively larger free diameter. The modules may, for instance, have a rectangular outer cross-sectional contour, for instance a square contour, and the sleeve opening may have a contour corresponding to the combined contour of a number of modules placed therein.
The sleeve and the washers will conveniently have mutually co-acting devices for maintaining the sleeve opening and the washer openings in correct alignment. These devices prevent relative rotation between the sleeve and respective washers. For instance, the washers may be provided with holes that receive projections on the axial ends of the sleeve to this end.
In one embodiment of the invention, the cable transit device may include four modules of square cross-section that together essentially fill the corresponding square opening through the rubber sleeve.
Respective modules may be divided in two parts in a plane axially to their throughpassing channels. The channel wall may consist of a tubular elastomeric element built-up of concentric layers which have a relatively low bonding strength in relation to each other, so as to enable the layers to be peeled one from the other and therewith adapt the size of the channel to the size of the cable concerned. The tubular rubber element that defines the channel through the module may be supported by a surrounding module part, which may also be elastically resilient, springy, so that the radially directed compression force from the rubber sleeve can be passed to its tubular sleeve and to the cable circumference via the module body.